relspecgo/cmd/relspec/templ.go

package main

import (
	"fmt"
	"os"

	"github.com/spf13/cobra"

	"git.warky.dev/wdevs/relspecgo/pkg/models"
	"git.warky.dev/wdevs/relspecgo/pkg/writers"
	wtemplate "git.warky.dev/wdevs/relspecgo/pkg/writers/template"
)

var (
	templSourceType      string
	templSourcePath      string
	templSourceConn      string
	templFromList        []string
	templTemplatePath    string
	templOutputPath      string
	templSchemaFilter    string
	templMode            string
	templFilenamePattern string
)

var templCmd = &cobra.Command{
	Use:   "templ",
	Short: "Apply custom templates to database schemas",
	Long: `Apply custom Go text templates to database schemas with flexible execution modes.

The templ command allows you to transform database schemas using custom Go text
templates. It supports multiple execution modes for different use cases:

Execution Modes:
  database  Execute template once for entire database (single output file)
  schema    Execute template once per schema (one file per schema)
  script    Execute template once per script (one file per script)
  table     Execute template once per table (one file per table)

Supported Input Formats:
  dbml, dctx, drawdb, graphql, json, yaml, gorm, bun, drizzle, prisma, typeorm, pgsql

Template Functions:
  String utilities:  toUpper, toLower, toCamelCase, toPascalCase, toSnakeCase, toKebabCase,
                     pluralize, singularize, title, trim, split, join, replace

  Type conversion:   sqlToGo, sqlToTypeScript, sqlToJava, sqlToPython, sqlToRust,
                     sqlToCSharp, sqlToPhp

  Filtering:         filterTables, filterColumns, filterPrimaryKeys, filterForeignKeys,
                     filterNullable, filterNotNull, filterColumnsByType

  Formatting:        toJSON, toJSONPretty, toYAML, indent, escape, comment

  Loop helpers:      enumerate, batch, reverse, first, last, skip, take, concat,
                     unique, sortBy, groupBy

  Safe access:       get, getOr, getPath, has, keys, values, merge, pick, omit,
                     sliceContains, indexOf, pluck

Examples:
  # Generate documentation from PostgreSQL database
  relspec templ --from pgsql --from-conn "postgres://user:pass@localhost/db" \
                --template docs.tmpl --output schema-docs.md

  # Generate one TypeScript model file per table
  relspec templ --from dbml --from-path schema.dbml \
                --template ts-model.tmpl --mode table \
                --output ./models/ \
                --filename-pattern "{{.Name | toCamelCase}}.ts"

  # Generate schema documentation files
  relspec templ --from json --from-path db.json \
                --template schema.tmpl --mode schema \
                --output ./docs/ \
                --filename-pattern "{{.Name}}_schema.md"`,
	RunE: runTempl,
}

func init() {
	templCmd.Flags().StringVar(&templSourceType, "from", "", "Source format (dbml, pgsql, json, etc.)")
	templCmd.Flags().StringVar(&templSourcePath, "from-path", "", "Source file path (for file-based sources, mutually exclusive with --from-list)")
	templCmd.Flags().StringVar(&templSourceConn, "from-conn", "", "Source connection string (for database sources)")
	templCmd.Flags().StringSliceVar(&templFromList, "from-list", nil, "Comma-separated list of source file paths to read and merge (mutually exclusive with --from-path)")
	templCmd.Flags().StringVar(&templTemplatePath, "template", "", "Template file path (required)")
	templCmd.Flags().StringVar(&templOutputPath, "output", "", "Output path (file or directory, empty for stdout)")
	templCmd.Flags().StringVar(&templSchemaFilter, "schema", "", "Filter to specific schema")
	templCmd.Flags().StringVar(&templMode, "mode", "database", "Execution mode: database, schema, script, or table")
	templCmd.Flags().StringVar(&templFilenamePattern, "filename-pattern", "{{.Name}}.txt", "Filename pattern for multi-output modes")

	_ = templCmd.MarkFlagRequired("from")
	_ = templCmd.MarkFlagRequired("template")
}

func runTempl(cmd *cobra.Command, args []string) error {
	// Print header
	fmt.Fprintf(os.Stderr, "=== RelSpec Template Execution ===\n")
	fmt.Fprintf(os.Stderr, "Started at: %s\n\n", getCurrentTimestamp())

	// Validate mutually exclusive flags
	if templSourcePath != "" && len(templFromList) > 0 {
		return fmt.Errorf("--from-path and --from-list are mutually exclusive")
	}

	// Read database using the same function as convert
	fmt.Fprintf(os.Stderr, "Reading from %s...\n", templSourceType)
	var db *models.Database
	var err error
	if len(templFromList) > 0 {
		db, err = readDatabaseListForConvert(templSourceType, templFromList)
	} else {
		db, err = readDatabaseForConvert(templSourceType, templSourcePath, templSourceConn)
	}
	if err != nil {
		return fmt.Errorf("failed to read source: %w", err)
	}

	// Print database stats
	schemaCount := len(db.Schemas)
	tableCount := 0
	for _, schema := range db.Schemas {
		tableCount += len(schema.Tables)
	}
	fmt.Fprintf(os.Stderr, "✓ Successfully read database: %s\n", db.Name)
	fmt.Fprintf(os.Stderr, "  Schemas: %d\n", schemaCount)
	fmt.Fprintf(os.Stderr, "  Tables: %d\n\n", tableCount)

	// Apply schema filter if specified
	if templSchemaFilter != "" {
		fmt.Fprintf(os.Stderr, "Filtering to schema: %s\n", templSchemaFilter)
		found := false
		for _, schema := range db.Schemas {
			if schema.Name == templSchemaFilter {
				db.Schemas = []*models.Schema{schema}
				found = true
				break
			}
		}
		if !found {
			return fmt.Errorf("schema not found: %s", templSchemaFilter)
		}
	}

	// Create template writer
	fmt.Fprintf(os.Stderr, "Loading template: %s\n", templTemplatePath)
	fmt.Fprintf(os.Stderr, "Execution mode: %s\n", templMode)

	metadata := map[string]interface{}{
		"template_path":    templTemplatePath,
		"mode":             templMode,
		"filename_pattern": templFilenamePattern,
	}

	writerOpts := &writers.WriterOptions{
		OutputPath: templOutputPath,
		Metadata:   metadata,
	}

	writer, err := wtemplate.NewWriter(writerOpts)
	if err != nil {
		return fmt.Errorf("failed to create template writer: %w", err)
	}

	// Execute template
	fmt.Fprintf(os.Stderr, "\nExecuting template...\n")
	if err := writer.WriteDatabase(db); err != nil {
		return fmt.Errorf("failed to execute template: %w", err)
	}

	// Print success message
	fmt.Fprintf(os.Stderr, "\n✓ Template executed successfully\n")
	if templOutputPath != "" {
		fmt.Fprintf(os.Stderr, "Output written to: %s\n", templOutputPath)
	} else {
		fmt.Fprintf(os.Stderr, "Output written to stdout\n")
	}
	fmt.Fprintf(os.Stderr, "Completed at: %s\n", getCurrentTimestamp())

	return nil
}